Blueberry bushes are arranged in long parallel rows. Blueberry harvesting machines are several feet long and look like an inverted U when observed from the front to back. The machines straddle the bushes as they move along the rows to pick the berries. Various means are used to loosen the berries from the bushes and dropping them onto leaves or scales that fill the space inside the bottom of the inverted U to collect the berries. The leaves are arranged in two parallel rows with a pivot on one end of each leaf connected to a bearing in a rail. The rails are attached to the inside surface or frame of the machine and run parallel to the rows of bushes when the machine runs over the bushes. The pivots are arranged on the rails so the leaves are tilted upward from front to back so they partially overlap one another like the scales on a fish. The free ends of the leaves in each row are also tilted slightly upward toward the center of the machine and slightly overlap the free ends of their mirror image counterparts on the opposite side of the machine. A row of leaves on one side of the machine is positioned directly opposite its mirror image counterpart in on the other side of the machine. They are called “leaves” apparently because they are roughly shaped like leaves or “scales” apparently because they overlap one another like the scales on a fish. For convenience, the word “scales” will be used hereinafter except when referring to prior art that uses the word “leaves”.
As the machine moves over the bushes the scales contact the bushes and rotate on their pivots while maintaining contact with the bushes. A spring connects each scale to the rail and by resisting movement of the scale helps to maintain the contact and return the scale to its resting position. Blueberry bushes do not have a single trunk or stem. Instead they branch out from the bottom into several stalks arranged in a roughly circular pattern. Since the scales are tipped upwards toward the center of the machine, the berries will roll from the center of the machine toward conveyers arranged along the sides of the machine. The conveyers then transport the berries into containers that are used to collect and store the berries. A description of typical blueberry picking machines can be found in U.S. Pat. Nos. 4,134,251, 5,113,644 and 5,259,177.
An important problem with the machines is their inability to harvest all of the berries that fall from the bushes. Since the scales can't cover all of the space under the bushes, a significant portion of the berries will fall onto the ground and are wasted. This results in a very substantial loss to berry farmers. It is highly desirable therefore to design the scales in such a way that they catch as many berries as possible. It is also highly desirable to avoid damage to the bark of the stalks when contacted by the scales. The bushes become more susceptible to disease when the bark is damaged.
U.S. Pat. No. 4,150,526 attempts to address the problem of waste by providing a collector leaf construction that includes a primary and a secondary leaf portion and claims that the separate movement of each portion covers more of the space under a blueberry bush thus reducing the waste from 35-50 percent to 15 percent (column 4, lines 53-59). U.S. Pat. No. 4,464,888 also addresses the problem of waste by employing a collector leaf having a particular shape, primarily a concave leading edge and a convex trailing edge. FIGS. 4 and 5 of that patent illustrate how that shape covers more of the space around a plant trunk or trellis post such as support grape bushes thereby producing a saving of 12 to 15 percent (column 4, lines 64-65). The rationale could not be equally applicable to blueberry bushes that do not have a single trunk or a supporting post. Instead they branch into several irregularly placed stalks.
The present invention not only addresses the objective of reducing waste but also reduces damage to the blueberry bushes. Because raspberries grow on several stalks per plant like blueberry bushes, the present invention is also useful for harvesting raspberries.